Recent statistics from the International Energy Agency (IEA) state that wasted standby power at home in OECD member countries amounts to 10% or more of average electricity consumption. The standby power of various electronic devices refers to the power consumed for various reasons even while a specific electronic device is not in use with the power plug connected with the electric outlet. One of the recent important issues for improving energy efficiency of various electronic devices is to effectively block the standby power.
Currently, a large number of chargers are used all over the world. It is known that about 4.8 billion chargers for mobile phones are used, and the number of chargers including chargers for various electric tools would be beyond all imagination.
Specifically, assuming that a user does not usually have the charger being charged for 20 hours a day in using the charger and the charger remains plugged in the electric outlet, it may be estimated that the average wasted standby power per corresponding charger is about 0.5 W. In this case, power of about 2.4 GWH may be unwittingly wasted a day in total. Accordingly, the standby power is equally wasted, and this may cause an economic loss resulting from generation of power corresponding to the wasted standby power. Further, use of fossil fuels may increase carbon dioxide levels, which finally brings about a multitude of problems, such as environmental pollution.
Typically, in chargers for charging batteries used in various electronic devices, even though charging is completed or the target device is separated from the charger, unless the power plug of the charger is physically separated from the electric outlet, the charger still wastes standby power, causing a waste of power.
Korean Patent No. 956,119 discloses a battery charger for blocking standby power and a control method thereof. Here, the charger includes a power-blocking unit, a power factor improvement unit, a power transformation unit, a transformed power-blocking unit, a battery charging unit, an overpower-blocking unit, an electric potential detection unit, a battery status detection unit, a battery connection detecting unit, battery capacity detecting unit and a program control unit. Since the charger of the above configuration adopts a power factor control unit for controlling reactive power and improving a power factor, it has a complicated configuration, and thus the manufacturing cost of the product may increase. Accordingly, it is needed to manufacture a battery-dedicated charger for blocking standby power with a simple configuration at a low cost, compared to the conventional chargers.
Korean patent No. 10-0981973 issued to the present applicant discloses a charger for mobile phones to block standby power by which AC power input to the charger is completely blocked, when a mobile phone or a battery case for charging is separated from the mobile phone charger, or the battery of the mobile phone is fully charged. Accordingly, the charger can effectively remove standby power that has been wasted in the typical mobile phone charger. However, the charger has a configuration mainly suitable for mobile phones. Therefore, it is still required to manufacture a charger for blocking standby power with a simpler configuration and a lower cost than those of the charger for mobile phones.